Call Weakness - an initial prompt string

[Dennis]

Currently, Called Weakness doesn't provide any prompt or indication that a Guardian can call out the effect. Can there be an initial prompt when you've reached the needed stacks on a target? I know it's not a quick-timed event, where you can't do it once the moment is over, but it would help with some of the obtuse nature of the ability.

Note that for current guardians, you can estimate it by enabling option 23, but you'll get a lot of other stuff, too.